The North Korean satellite launched into space last week is out of control and most likely dead, astronomers reported Monday.

The apparent failure will not cause the spacecraft to fall quickly back to Earth but represents a major setback in Pyongyang's bid to portray the launching as a patriotic and technological success.

"It's tumbling, and we haven't picked up any transmissions," said Jonathan McDowell, a Harvard astronomer who tracks global rocket launchings and space activity. "Those two things are most consistent with the satellite being entirely inactive at this point."

North Korea's state-run media, which were preoccupied Monday with reporting on the somber first anniversary of the death of Kim Jong Il, the longtime leader, said nothing about the satellite's dysfunction. It has been describing the satellite launching as a triumphal achievement of Kim's successor, his son Kim Jong Un, done in the face of worldwide criticism and U.N. sanctions on the North's ballistic missile program.

The satellite, said to be about the size of a washing machine, reportedly carries an onboard camera to observe the Earth. That mission requires the spacecraft's orbit to be rock steady.

McDowell said the tumbling implies that onboard systems meant to control and stabilize the craft had failed.

He added that radio astronomers had picked up no signals from the satellite and that optical astronomers had observed it brightening and dimming as it slowly tumbled end over end.

"It's clear that the rocket part of this mission worked very well for the North Koreans," McDowell said. "They ended up in the right orbit. But the preponderance of the evidence suggests that the satellite failed either during the ascent or shortly afterwards."